This application relates to new dyes and to dyeing of fibers, more particularly, to new phosphorus acid dyes which in use become covalently linked through a condensation residue to sites on the fiber.
The novel class of dyes here disclosed is characterized by a chromophore attached to a triazine ring. As starting materials, a large class of such materials having two halogen atoms attached to the triazine ring are already known, as discussed below. Such dyes are reacted with two moles of an aminophenyl phosphonic or phosphoric acid of the type described to produce the novel dyes of the invention. These are represented by the formula: ##STR2## where D represents a chromophore and each of R and R' is preferably either ##STR3## (preferably in the meta position) or ##STR4## (preferably in the para position with respect to the amino group). R is preferably the same as R'. Less preferably, one of R and R' may be ##STR5## and the other ##STR6## or the total of R and R' may be composed of varying proportions of ##STR7##
The exact structure of the chromophore is not critical and may derive from a wide variety of dye structures. These latter, when combined with dihalotriazine radicals, constitute what are known conventionally as reactive dyes. Illustrative reactive dyes used as starting materials include: ##STR8## Other suitable starting dyes will be apparent to one skilled in the art.
The dyes of the invention have the particular advantage that they start from a wide variety of conventional reactive dyes of known shades. By incorporation of aminophenyl phosphonic and/or phosphoric radicals, one may, at will, develop a new line of dyes having generally predictable shades, without significant color shift. The dyes of the invention are, furthermore, highly superior in their hydrolytic and storage stability, compared with the instability and other handicaps of the conventional halotriazine dyes.
These novel dyes are particularly useful in that they can be chemically bound to cellulosic and other fibers and exhibit excellent color fixation. They become covalently linked to cellulose fibers by means of a phosphorus ester link produced in the presence of a carbodiimide, such as cyanamide. Such procedures are described in detail in German Offen. Publication No. 25 05 497 of Aug. 14, 1975, the disclosure of which is hereby incorporated by reference.